Sciencemadness Discussion Board

Sodium Metal from NaCl

Khemeia - 15-10-2015 at 10:30

How practical would produce NaOH from the electrolysis of a supersaturated NaCl solution; then electrolyze the dried molten NaOH in a steel pot under a high melting point wax?

[Edited on 15-10-2015 by Khemeia]

Detonationology - 15-10-2015 at 10:32

Electrolysis of a supersaturated NaCl solution typically produces sodium chlorate or perchlorate. btw, what are you trying to produce? The subject suggests that you wish to make "sodium metal" and message suggests that you wish to make NaOH. Sodium metal can be made by the electrolysis of a sodium salt, typically NaOH is what is used because of the low melting point. Is that what you meant? If so, check this thread out.
[Edited on 10-15-2015 by Detonationology]

[Edited on 10-15-2015 by Detonationology]

Khemeia - 15-10-2015 at 10:38

Yes, but I'd rather convert it to NaOH before melting because NaOH has a much lower melting point than NaCl. It's more of a proof of concept rather than anything practical.

Detonationology - 15-10-2015 at 10:44

Just so I understand correctly: your main goal is to produce sodium metal. You wish to preform electrolysis on NaOH to make sodium metal. You need to convert NaCl into NaOH in order to preform the electrolysis.

Khemeia - 15-10-2015 at 10:49

That is correct.

Detonationology - 15-10-2015 at 10:56

Hmm... converting the NaCl to NaOH seems to be the biggest struggle here. Where do you live? Sodium hydroxide is sold in hardware stores as a crystal drain opener; however, if you live in a more remote part of the world, NaOH can be made by mixing wood ashes with water. The metal oxides will be converted to hydroxides, which can be filtered and evaporated to collect the metal hydroxide. Then a sodium salt can be added to ensure sodium hydroxide.

[Edited on 10-15-2015 by Detonationology]

Khemeia - 15-10-2015 at 11:01

Buying bulk NaOH but what sort of effort would have to be put in to convert NaCl to NaOH?

MrHomeScientist - 15-10-2015 at 11:05

I make a weak solution of base by electrolyzing salt water in a membrane cell, using a standard clay flowerpot as the membrane. It is extremely slow and impractical. Especially if you can just buy it in bulk.

Detonationology - 15-10-2015 at 11:06

No need to make sodium hydroxide if it can be purchased at an affordable price, unless this experiment is for the sake of science.

[Edited on 10-15-2015 by Detonationology]

aga - 15-10-2015 at 11:29

Quote: Originally posted by Detonationology  
NaOH can be made by mixing wood ashes with water

Leeching wood ashes tends to yield a good mix of 'stuff'.

AFAICR the main product is KOH.

blogfast25 - 15-10-2015 at 11:55

Quote: Originally posted by aga  

AFAICR the main product is KOH.


Potash actually: K2CO3.

AJKOER - 15-10-2015 at 16:10

"Down's process
In this process, molten sodium chloride (common salt) is electrolyzed using a graphite anode and a ring shaped iron cathode. The two electrodes are separated by a wire gauge partition to avoid the mixing of sodium and chlorine so formed. As Sodium chloride melts at a very high temperature of 1085 K, a mixture containing sodium chloride, potassium chloride and potassium fluoride (NaCl + KCl + KF) is employed. This mixture melts at about 850-875 K....."

Link: http://chem-guide.blogspot.com/2010/04/sodium-occurrence-ext...
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Here is a YouTube on Na preparation via a Mg path:
http://www.youtube.com/watch?v=faorfmRkCv0

[Edited on 16-10-2015 by AJKOER]

m1tanker78 - 15-10-2015 at 18:58

Quote: Originally posted by Khemeia  
How practical would produce NaOH from the electrolysis of a supersaturated NaCl solution; then electrolyze the dried molten NaOH in a steel pot under a high melting point wax?

[Edited on 15-10-2015 by Khemeia]


Do you have a specific wax in mind? I don't think any wax would withstand the abuse of such high temperatures and molten NaOH. That goes for most organic compounds that would be liquid in the molten NaOH temperature neighborhood.

Definitely buy some NaOH if you're hell-bent on using NaOH. Invest in some safety gear as well. If you have a means to construct a cell, check out the thread(s) already referenced here.

A Downs cell takes NaCl (and optionally other salts) but has a huge learning curve and operates under more extreme conditions.